Genome-Wide Analysis on the Landscape of Transcriptomes and Their Relationship With DNA Methylomes in the Hypothalamus Reveals Genes Related to Sexual Precocity in Jining Gray Goats.

Feng Su,Yanchao Wang,Yuding Wang,Yunliang Jiang,Xiaoli Guo,Guiling Cao

doi:10.3389/fendo.2018.00501

Feng Su, Yanchao Wang + Show 4 more

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https://doi.org/10.3389/fendo.2018.00501

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Abstract

The Jining Gray goat is famous for its sexual precocity; however, the exact regulatory mechanism is still unknown. The hypothalamus is the key centrum in the process of animal reproduction, especially in signal transduction, and the initiation of puberty. The identification of potential genes and pathways in the hypothalamus of Jining Gray goat is critical to understanding the regulatory mechanism of sexual precocity in these goats. In this study, mRNA transcriptome analysis of the hypothalamus of juvenile and pubertal goats revealed eight genes (NTS, ADORA1, CRH, UCN3, E2F2, PDGFRB, GNRH1, and CACNA1C) and three pathways [neuroactive ligand-receptor interaction; gonadotropin-releasing hormone (GnRH) signal; melanoma] that are involved in this regulation. Subsequent methylation analysis on differentially methylated region (DMR) genes revealed the potential regulation network that influences pubertal onset. Correlation analysis verified the methylation level of some DMR genes correlates negatively with expression level. Integrated analysis between transcriptomes and methylomes identified 80 candidate genes involved in GnRH and neuroactive ligand signal pathways, of which CACNA1C and CRH were differentially expressed genes (DEGs) influenced by methylation level. The GnRH gene was the only DEG not affected by its methylation level. In summary, in this study, we identified eight genes and three pathways that are related to pubertal onset in Jining Gray goats, and the expression of CACNA1C and CRH genes of the GnRH and neuroactive ligand signal pathways were influenced by DNA methylation, while that of the GnRH gene was not affected.

Highlights

The Jining Gray goat, one of the local breeds in the southwest of Shandong province, China, is characterized by its fertility performance
Differentially Expressed Gene (DEG) were screened according to the criterion of fold-change ≥ 2 and False Discovery Rate (FDR) ≤ 0.01, and hierarchical clustered maps revealed 180 annotated genes that are differently expressed in these two phases (Supplementary Table 1, Figure 1B)
To explore genes and pathways affecting the sexual precocity of the reproductive performance of Jining Gray goats, hypothalamus transcriptomes was evaluated in this study

Summary

Introduction

The Jining Gray goat, one of the local breeds in the southwest of Shandong province, China, is characterized by its fertility performance. The sexual maturity time of Jining Gray goats (90 days) is significantly earlier than for Boer goats (157.2–191.1 days) [2], Angora goats (180–240 days) and Inner Mongolia Cashmere goats [3] This performance has been extensively applied to increase goat husbandry production; the underlying biological mechanisms remain unknown. Existence and release of gonadotropins maintains the mammalian estrous cycle, and influences oocyte development and ovulation in female mammals [6] Another critical function of the hypothalamus is related to its complicated regulatory mechanism, the major regulation of FSH and LH secretion through stimulating hypothalamic GnRH and the feedback from the gonadal gland [7, 8], and the putative LH regulator PACAP regulation pathway that contribute to the oocyte maturation and ovulation [9, 10]. The physiological role of the hypothalamus in the accurate regulation of gonadotropin secretion is still poorly understood

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